I suspect a drafting error in the wording. If you are bearish in the USD you would want to sell USD/XXX or buy XXX/USD.
So let’s suppose the word should have been bullish, rather than bearish. But it’s a good question - how does checking CHF/JPY tell you which USD-based pair against one or the other tell you which one to buy. It’s simple - if CHF/JPY is rising, then CHF is stronger than JPY, JPY is weaker than CHF. So as your target buy trade benefits from a strong USD and a weak counter currency, the weaker the counter currency the better for you. So you would buy USD/JPY.
And of course if CHF/JPY was falling, you would buy USD/CHF.
If you’re bearish on the U.S. dollar, you might consider trading pairs like CHF/JPY to indirectly express your bearish view on USD, as both CHF and JPY tend to move against the dollar.